Check out this outstanding site about the chlorination of toluene. All is answered, from the spectrum of light wwhich is ideal (blue) to temperatures to the amount of moles of chlorine. About 2.07 moles is optimal, which yields mostly benzalCl, and benzylCl.
http://www.faizkaskar.8k.com/p.html (http://www.faizkaskar.8k.com/p.html)
If you don't have the capability to fractionally distill it's difficult to isolate benzaldehyde.
Benzoic acid can be basified to sodium benzoate, making it then soluble to wash out with water.
What I'm saying is, almost always you'll want several steps or reactions to reach a high yield from the origional feedstock-toluene. i.e The first reaction, then separation via distillation, and then a reaction for 2 or 3 of the fractions, whatever they may be.
BenzylCl, BenzylOH, BenzalCl, benzotrichloride, benzoic acid.
The benzal is easily converted, however you need to separate and work out what you'll be doing with the others. Benzyl OH is easy to. benzyl Cl just needs further chlorination.
>>ooh one thing, benzyl chloride is explosive, it would be much preferable if it were not dealt with for very long nor at much temperature...
Actually if you run the reaction at low temperatures it causes chlorination of the benzene ring so get over it, to put it bluntly. ~100C is a good temperature.
I've never read about much emphasis being placed on the explosiveness of benzyl chloride, it can't be too bad?
It isn't cheap or easy making benzaldehyde I found after investigation. But more easy than cheap...
E.g to produce 1 mole of Cl will require 4 moles/400-500ml of HCl 31.4% solution if the MnO2 route to Cl is used. This will give you ~100ml of benzyl chloride (like wow...) if yields are 100%.
Benzyl chloride isn't even what you want; it isn't enough to kill the stress even if it was magically benzal chloride, etc etc.
Hypochlorite might be a much better option, if you can fractionally distill. otherwise it's likely to be another gay day. :D
Watching TV and not stressing is the best bet, no evil thoughts of making chemicals etc, until tomorrow- then it's okay.
elfspice i noticed a mistake
PhCH2Cl+H20-->PhCH20H+HCl
not PhCH2Cl+H20-->PhCH20+HCl+1/2H2
and as rhodium stated, benzyl chloride is not any more flammable/explosive then a similiar molecular wieght hydrocarbon, but the shit is like tear gas, open the stopper for about 5sec outside a fume hood with no gas mask and youll be cryin for a half hour.
however there are some explosive possibilities when heating any organic with a pure hypochlorite.
an alternative pathway is air oxidation of toluene by passing toluene vapor and air over a catalyst.
for instance http://www.faizkaskar.8k.com/processelection.html (http://www.faizkaskar.8k.com/processelection.html)
claims that a V2O5/K2SO4 catalyst is the most selective for this transformation giving yield of 60%.
it uses air at 1atm and temps of 400C.
other information on that site seems to indicate benzaldehyde formation is favored by a low conversion rate per pass, indicating that using a less then stochiometric 02 to PhCH3 feed rate is optimal, it also states that a contact time of 0.1-1.0 sec between the vapour and catalyst is optimal.
in many ways this procedure should not be any more difficult to setup and aquire needed materials then the hypochlorite synth.
THis is an interesting titbit of info I found whilst surfing google.Dont know how serious it is but.
I recall Dwarfer mentioning using ttt as a chlorinating agent a while back.
Organikum has posted a patent of late, which claims the addition of hexamine avoids ring chlorination.
He also describes a process in which mixtures of benzyl and benzal chloride are treated with aqueous hexamine sollution to yield benzaldehyde.
Once the fucking serch engine is fixed you can look it up for your own.
For those of you that have chlorinated toluene with Cl2, you know how messy
it is. The endpoint is coneviently determined by bp of the solution, but the
HCl that's given off makes for a mess. The fume hood rots, rubber tubing
that conducts the HCl to a trap rots, and the trap has to be carefully
constructed or water will back up into your reaction (shut down and run
time!)!!!! Throughout the reaction, the HCL is pulling benzyl chloride over
into the trap, and hey, it's a mess!
Trichloro triazine trione (TTT) is a cholrinating agent used for swimming
pools and powerful cleansers, the pool type being pressed into 5-7 cm dia
tablets, and available at most US hardware stores. You put a tablet into a
plastic bag and crush it into a powder with a hammer (or squeeze it in a
vise). Put about 300ml of toluene and a large stribar in a 1 liter Erlenmyer
flask on a stir/hotplate. Fit the flask with a short, wide bore, straight,
water cooled condenser and bring the toluene to reflux under stir. Aim a
powerful (150 watt) lamp at the reaction, and add spoonfuls of TTT
cautiously, down through the condenser, watching for a vigorous reaction,
most notably by observing the level where vapors condense in the condenser.
DO NOT OVERFEED THE REACTION. Add a few drops of water (if necessary) to
begin the reaction.
The TTT releases HOCL on contact with water, along with some free Cl2. The
Cl2 reacts at the methyl of the toluene and releases HCl. The HCl goes back
to the TTT and realeases CL2. The beauty of this is that you don't need to
mess with gaseous CL2, and the HCl is recycled! It's cheap, quick, and the
TTT reaction product (cyanuric acid) is easily filtered off from the
finished reaction mixture. Workup consists of simple distillation, after a
quick filtering and water/carbonate wash.
I've only tried this with toluene, but my suspicion is that the in-situ
generation of chlorine will be effective with many substrates. Small scale
experiments, with a few mL in a test tube very conveniently demonstrate the
effect of actinic light on the free radical generation aspect of the
reaction: heat the mixture over a small flame until just at the boiling
point, and expose the test tube to a powerful light. While in the light, the
reaction is vigorous; when the light is turned off, the reaction subsides. A
great demo for the classroom!
http://list.pengus.net/pipermail/chemfan/2002/000031.html (http://list.pengus.net/pipermail/chemfan/2002/000031.html)
I recall Dwarfer mentioning using ttt as a chlorinating agent a while back.
Yeah SWIM was just about to suggest that, as he just remembered reading that thread. SWIM hasn't tried it but it probably is the best route to take.
And BOS, you are damn right about the Cl2 chlorination. I wouldn't try it again in a million years. The only reason why SWIM did it the first time was because money was tight, and it was out of pool season for the LiOCl. So it was easy enough to use bleach and muriatic SWIM had laying around to make the Cl2 gas. Two kneck rb flask equipped with one hole stopper and pressure equalized add. funnel charged with bleach was used, and the muriatic was dripped in. The gas was led via tube to another two kneck rb with one hole stoppers in each kneck, for suckback trap. That was led via tubing into a third larger 2 kneck that held the stones and some toluene, topped off with friedrichs condensor. The top of the freidrichs was sealed off with a straight vacuum adaptor (not angled like those for distilling), that was sealed with a glass stopper. The hose barb on the vacuum adaptor had some tubing attatched that SWIM ran out a window (he was in a secluded area).
SWIM used the same setup for LiOCl chlorination, minus the gassing apparatus. The second kneck on the still flask was stoppered with glass stopper, and periodically removed for placement of large powder funnel for LiOCl addition. It was quite easy. Yeilds were average (SWIM also got horrible yeilds when using Cl2). Sunlight was used as light source.
Amalgan stated that SWIM used tubing to bubble Cl2 through the toluene. I am wondering what kind of tubing this was as toluene dissolves most plastics and polymers. Was it glass or teflon or is there a widely available plastic that is resistant to toluene. Concerning TTT method to benzyl chloride, I think it does work, but benzoyl peroxide is necessary as a radical initiator. I quote from https://www.thevespiary.org/rhodium/Rhodium/pdf/trichloroisocyanuric.pdf (https://www.thevespiary.org/rhodium/Rhodium/pdf/trichloroisocyanuric.pdf)
:
"Toluene gave the 2- and 4-chlorotoluenes under acidic conditions (66%). The main regioisomer was the 4-chlorotoluene. With phenol and aniline the yield was lower giving mainly the para isomer. With electron withdrawing groups no reaction occurred (Scheme 12). Alternatively when benzoyl peroxide was used as radical initiator, benzylchloride was obtained in 44% from toluene."
This is straight from the journal of Organic Process Research and Development, so I think its fairly reliable. Perhaps in Organikum's experiment he neglected to use benzoyl peroxide.